A respected engineer and retired Navy officer sexually abused a teenage relative for more than a year, a Charleston County jury found.

Erick Alberto Arroyo, a 54-year-old Mount Pleasant man, was convicted Friday on two counts of second-degree criminal sexual conduct with a minor and lewd act on a minor. Arroyo must undergo a psychological evaluation prior to his sentencing to determine if he will be classified as a sexual predator.

A 13-year-old girl came forward in 2009 with information that Arroyo, a relative, had abused her for more than a year. Prosecutors said the girl’s mother found Arroyo on top of her daughter.

The girl, now 16, testified in court that Arroyo told her he wanted to teach her about sex so she wouldn’t have to experiment with boys, prosecutors said. His abuse progressed from fondling to sex.

Assistant Solicitor Elizabeth Gordon said the girl took a risk by speaking up and that some family members disowned her because of it.

“It took a great deal of courage to confront the man who had done this to her and to have to testify in great detail in front a room full of strangers about abuse that she so desperately would prefer to forget,” Gordon said in a written statement. “It was obvious the victim was telling the truth, and I am very pleased that the jury could see that.”

The jury heard five days of testimony before deliberating less than four hours to return its guilty verdict, according to prosecutors. Arroyo faces up to 20 years in prison on the sexual conduct counts and up to 15 years in prison on the lewd act count.

Reach Allyson Bird at 937-5594 or Twitter.com/allysonjbird.